Recently, Yunnan Electric Science Academy, Xi'an Jiao Tong University and Northwestern Polytechnical University have jointly developed the first 10kV outdoor high pressure load switch which adopts a new type of environmental protection mixture as insulation medium. It is the first creation in the country. And the related type test has been passed in the quality supervision and inspection of the national high voltage electrical apparatus.

It is understood that the new type of environmental mixed gas insulation used in the load switch is better than the six sulfur fluoride SF6 used in the current switch equipment, and has the characteristics of compact structure, friendly environment, superior performance and so on. By adjusting the mixture gas ratio, the minimum working environment temperature requirements of -25 C and even -30 C can be met, and the ozone layer is not destroyed, which can greatly reduce the adverse effects of the switch equipment on the environment.

SF6 is the most widely used gas insulating medium and arc extinguishing medium in power system. It is also a very strong greenhouse gas and has great influence on global warming. The global temperature increasing potential (GWP) of the new environment-friendly insulating gas is only 4%~2% of SF6. Under the same dosage, the use of the gas switch equipment can reduce the CO2 emission by 96%~98% in the whole life cycle, and it is obvious to suppress the global warming. In addition, as the insulation strength of the new gas is higher than SF6, the switch equipment can work under the state of "micro negative pressure". It will be able to effectively solve the "drum" problem of the conventional switching equipment to be applied to the plateau area after inflating in the plain area. It is especially suitable for high altitude areas such as Yunnan and Guizhou.

Next, the technology will take the lead in the pilot projects of Yunnan Power Grid Co. In addition to the 10kV outdoor high-voltage switch, the Yunnan Electric Power Research Institute will also apply the new environmental protection gas cabinet in other medium pressure gas insulated switchgear.